/* tslint:disable */
import * as objects from '@vscode-alt/monaco-editor/esm/vs/base/common/objects';
import * as arrays from '@vscode-alt/monaco-editor/esm/vs/base/common/arrays';
import * as types from '@vscode-alt/monaco-editor/esm/vs/base/common/types';
import { IConfigurationModel, IOverrides,
} from '../../../interfaces';
import { removeFromValueTree, getConfigurationValue, addToValueTree } from '../helpers';

export class ConfigurationModel implements IConfigurationModel {

	private isFrozen: boolean = false;

	constructor(
		private _contents: any = {},
		private _keys: string[] = [],
		private _overrides: IOverrides[] = []
	) {
	}

	get contents(): any {
		return this.checkAndFreeze(this._contents);
	}

	get overrides(): IOverrides[] {
		return this.checkAndFreeze(this._overrides);
	}

	get keys(): string[] {
		return this.checkAndFreeze(this._keys);
	}

	isEmpty(): boolean {
		return this._keys.length === 0 && Object.keys(this._contents).length === 0 && this._overrides.length === 0;
	}

	getValue<V>(section: string | undefined): V {
		return section ? getConfigurationValue<any>(this.contents, section) : this.contents;
	}

	override(identifier: string): ConfigurationModel {
		const overrideContents = this.getContentsForOverrideIdentifer(identifier);

		if (!overrideContents || typeof overrideContents !== 'object' || !Object.keys(overrideContents).length) {
			// If there are no valid overrides, return self
			return this;
		}

		let contents = {};
		for (const key of arrays.distinct([...Object.keys(this.contents), ...Object.keys(overrideContents)])) {

			let contentsForKey = this.contents[key];
			let overrideContentsForKey = overrideContents[key];

			// If there are override contents for the key, clone and merge otherwise use base contents
			if (overrideContentsForKey) {
				// Clone and merge only if base contents and override contents are of type object otherwise just override
				if (typeof contentsForKey === 'object' && typeof overrideContentsForKey === 'object') {
					contentsForKey = objects.deepClone(contentsForKey);
					this.mergeContents(contentsForKey, overrideContentsForKey);
				} else {
					contentsForKey = overrideContentsForKey;
				}
			}

			contents[key] = contentsForKey;
		}

		return new ConfigurationModel(contents);
	}

	merge(...others: ConfigurationModel[]): ConfigurationModel {
		const contents = objects.deepClone(this.contents);
		const overrides = objects.deepClone(this.overrides);
		const keys = [...this.keys];

		for (const other of others) {
			this.mergeContents(contents, other.contents);

			for (const otherOverride of other.overrides) {
				const [override] = overrides.filter(o => arrays.equals(o.identifiers, otherOverride.identifiers));
				if (override) {
					this.mergeContents(override.contents, otherOverride.contents);
				} else {
					overrides.push(objects.deepClone(otherOverride));
				}
			}
			for (const key of other.keys) {
				if (keys.indexOf(key) === -1) {
					keys.push(key);
				}
			}
		}
		return new ConfigurationModel(contents, keys, overrides);
	}

	freeze(): ConfigurationModel {
		this.isFrozen = true;
		return this;
	}

	private mergeContents(source: any, target: any): void {
		for (const key of Object.keys(target)) {
			if (key in source) {
				if (types.isObject(source[key]) && types.isObject(target[key])) {
					this.mergeContents(source[key], target[key]);
					continue;
				}
			}
			source[key] = objects.deepClone(target[key]);
		}
	}

	private checkAndFreeze<T>(data: T): T {
		if (this.isFrozen && !Object.isFrozen(data)) {
			return objects.deepFreeze(data);
		}
		return data;
	}

	private getContentsForOverrideIdentifer(identifier: string): any {
		for (const override of this.overrides) {
			if (override.identifiers.indexOf(identifier) !== -1) {
				return override.contents;
			}
		}
		return null;
	}

	toJSON(): IConfigurationModel {
		return {
			contents: this.contents,
			overrides: this.overrides,
			keys: this.keys
		};
	}

	// Update methods

	public setValue(key: string, value: any) {
		this.addKey(key);
		addToValueTree(this.contents, key, value, e => { throw new Error(e); });
	}

	public removeValue(key: string): void {
		if (this.removeKey(key)) {
			removeFromValueTree(this.contents, key);
		}
	}

	private addKey(key: string): void {
		let index = this.keys.length;
		for (let i = 0; i < index; i++) {
			if (key.indexOf(this.keys[i]) === 0) {
				index = i;
			}
		}
		this.keys.splice(index, 1, key);
	}

	private removeKey(key: string): boolean {
		let index = this.keys.indexOf(key);
		if (index !== -1) {
			this.keys.splice(index, 1);
			return true;
		}
		return false;
	}
}